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Short‑course sublingual ITULAZAX birch pollen extract with Lactobacillus rhamnosus GG for patients with pollen‑associated food allergy

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What is this trial about?

A plain-language summary of the goals, design and what participants do

People who are allergic to birch pollen often develop a related reaction to certain foods, especially apples; this is known as Pollen-associated Food Allergy. The underlying trigger is a sensitivity to birch pollen, called Birch pollen Allergy. The trial tests a new treatment that delivers small amounts of birch pollen extract under the tongue (sublingual administration) to help the immune system become less reactive. The product being studied is named ITULAZAX, and it is compared with an inactive substance, referred to as placebo.

The purpose of the study is to determine whether a short‑course of this sublingual therapy can lessen the symptoms that appear after eating a controlled amount of apple, known as an apple challenge. Participants will be randomly assigned to receive either the active drops or the inactive drops for several weeks, then they will attend a series of visits where they will eat the test apple and report any itching, stinging, or other reactions. Throughout the study, safety checks such as physical examinations and basic lab tests will be performed, and any side effects will be recorded.

The research process

The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial visit and consent

    After enrollment you attend the first study visit where informed consent is confirmed and eligibility is verified.

    Baseline assessments are performed, including medical history, physical examination, and collection of blood samples for allergy testing.

  2. Step 2

    Baseline assessments and randomization

    You complete questionnaires that evaluate allergy symptoms and quality of life.

    Study staff assign you to receive either the active medication itulazax or the placebo without revealing the assignment.

  3. Step 3

    Start of medication

    You begin taking the study medication as instructed.

    The active product itulazax 12 sq-bet lyophilisat is administered sublingually (under the tongue) as a single lyophilisate dose of 1 unit per administration.

    If assigned to the probiotic arm, you take infectodiarrstop lgg oral suspension, 1.34 g per dose.

    The frequency and total duration of intake follow the short‑course schedule defined by the trial protocol.

  4. Step 4

    Interim study visits

    You attend scheduled visits to monitor safety and adherence.

    At each visit you report any side effects, receive a physical check, and may have additional blood samples taken.

    The study medication is dispensed for the next interval and any unused dose is returned for accountability.

  5. Step 5

    Final visit and apple challenge

    You undergo a standardized apple challenge in which a measured amount of apple is consumed to assess allergic reaction.

    Symptoms such as itching, stinging, or prickling are recorded using a visual analogue scale within five minutes after the challenge.

    Final questionnaires, physical examination, and laboratory tests are performed to evaluate changes from baseline.

    Use of rescue medication (ceterizine or prednisolon) is recorded if needed.

Who can join the trial?

11 criteria

  • You agree to sign a written informed consent form.
  • You have had a birch‑pollen related food problem for more than 2 years, with noticeable reactions when eating apples, and you scored at least 2 on a food‑allergy questionnaire (FAQLQ/FAIM).
  • Blood tests show you are sensitive to apple, measured by a specific IgE test against Mald1 that is higher than CAP class 1.
  • You are between 18 and 65 years old, regardless of gender.
  • If you are a woman who could become pregnant, a blood beta‑HCG test must be negative during screening.
  • If you are a woman who could become pregnant, a urine pregnancy test must be negative on the day you are randomly assigned to treatment.
  • If you are a woman who could become pregnant, you must use a reliable birth control method (examples: hormonal pills, implant, intrauterine device, partner’s vasectomy, etc.).
  • Blood and skin testing show you are sensitive to birch pollen, with a skin prick test wheal larger than 5 mm and a specific IgE level against Betv1 higher than CAP class 2.
  • After a controlled apple challenge, you must rate the itch, stinging or prickling feeling at least 3 on a visual analog scale (VAS) (0‑10) within 5 minutes.
  • You are able to understand what the study involves and can work with the study staff.
  • You have had moderate to severe allergic rhinitis (runny nose) and/or conjunctivitis (eye irritation), with or without asthma, caused by birch pollen for more than 2 years.

Who cannot join the trial?

20 criteria

  • Pregnancy, planning to become pregnant, or breastfeeding – you cannot be pregnant, trying to get pregnant, or nursing a baby.
  • Significant psychiatric disorder – having a current mental health condition that is important to your care.
  • Use of certain medicines – taking or having recently taken beta‑blockers, ACE‑inhibitors, systemic steroids, immune‑suppressants, antidepressants, neuroleptics, or biologic drugs.
  • Severe allergic reaction (anaphylaxis) to birch‑related foods or more than two serious allergic reactions affecting the whole body.
  • Participation in another clinical trial – being in another study or having taken another study drug within the past four weeks.
  • History of throat swelling (laryngeal edema) after eating birch‑related foods.
  • Current hives (urticaria) or deep skin swelling (angioedema) that is still a problem.
  • Very high itch or sting feeling (a visual analog scale score of 9 or higher) after a controlled apple test before randomization.
  • Sensitization to stable food proteins (nsLTP) or other heat‑stable allergens, shown by a specific IgE blood test above a low level and symptoms when eating cooked fruit.
  • Allergy to any ingredients in the study drug, including D‑glucose, saccharose, aspartame, maltodextrin, sodium ascorbate, fish‑source gelatin, mannitol, or sodium hydroxide.
  • Allergy to rescue medication ingredients (cetirizine, hydroxyzine, prednisolone) or having severe kidney disease with an estimated glomerular filtration rate (eGFR) below 15 ml/min.
  • Uncontrolled asthma or reduced lung function – forced expiratory volume in one second (FEV1) less than 80% of the normal predicted value.
  • Elevated serum tryptase or mastocytosis – high blood levels of an enzyme released by mast cells, or a condition with too many mast cells.
  • Severe eczema (atopic dermatitis) that is currently significant.
  • Current eosinophilic esophagitis – inflammation of the food pipe involving a type of white blood cell called eosinophils.
  • Acute severe mouth inflammation or mouth wounds that are present now.
  • Allergen‑immunotherapy within the past five years – having received allergy shots or drops in the last five years.
  • Other immune‑system diseases needing treatment, such as active autoimmune diseases, cancer, or ongoing infections.
  • Serious medical conditions requiring treatment, including diabetes, severe high blood pressure, or major kidney, liver, gut, or heart disease.
  • Current serious addiction to alcohol or drugs.
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Investigated drugs

  • ITULAZAX

    is a sublingual (under the tongue) lyophilisate that contains a birch pollen extract. In the study it is given to try to “teach” the immune system to become less reactive to birch pollen, which can also trigger food‑related allergy symptoms. By placing the tablet under the tongue, the pollen proteins are absorbed through the mouth lining, aiming to reduce allergy reactions during a later apple challenge.

  • INFECTODIARRSTOP® LGG® Mono

    is an oral suspension that provides a probiotic strain called Lactobacillus rhamnosus GG. The product is mixed with water to make a drink that infants and young children can take. In the trial it is used to support healthy gut bacteria, which may help the immune system respond more calmly to allergens and potentially lessen food‑allergy symptoms.

What is already known about the treatment

  • ITULAZAX

    This sublingual lyophilisate is placed under the tongue where it quickly dissolves and the birch pollen extract is absorbed through the mouth lining. It is currently an investigational product being studied in clinical trials and is not yet approved for routine use. The preparation is intended to reduce symptoms of birch pollen allergy and related food reactions, such as apple allergy. It works by repeatedly exposing the immune system to small amounts of birch pollen proteins, which helps the body become tolerant and shifts the immune response away from allergy‑driven activity. It belongs to the class of allergen immunotherapy products (tree pollen extract).

  • INFECTODIARRSTOP® LGG®

    This oral suspension is mixed with water to form a drink that infants and young children can swallow. The probiotic Lactobacillus rhamnosus GG is already marketed as a dietary supplement and is widely used, though its use for preventing diarrhea in this trial is still being evaluated. It is meant to support gut health and help prevent infectious diarrhea in babies and toddlers. The live bacteria colonize the intestine, compete with harmful microbes, and gently modulate the immune system to maintain a balanced gut environment. It is classified as a probiotic, a live bacterial preparation used for gastrointestinal health.

Investigated diseases

  • Pollen-food allergy syndrome

    It is an allergic condition where people who are sensitized to pollen experience itching, swelling, or tingling in the mouth and throat after eating certain raw fruits, vegetables, or nuts that contain proteins similar to pollen. The reaction usually starts within minutes of eating the trigger food and may spread to other parts of the mouth. Symptoms can become more intense with higher exposure to the pollen season. Repeated exposure can lead to a broader range of foods causing symptoms. The condition often follows the seasonal pattern of the related pollen.

  • Birch pollen allergy

    It is an allergic response to proteins found in the pollen of birch trees. When birch pollen is inhaled, the immune system reacts, causing sneezing, runny nose, itchy eyes, and sometimes nasal congestion. Symptoms typically appear in spring when birch trees release pollen and lessen as the pollen count drops. Repeated seasonal exposure can increase the sensitivity of the reaction. The allergy may persist for many years, with symptom intensity varying from season to season.

Trial detailsLast updated 4 Oct 2026
Age18+ yearsPhasePhase IITrial ID2025-523653-34-00Protocol codeSIPA1-2024Estimated enrolment96 patientsSponsorKlinikum der Technischen Universitaet Muenchen (TUM Klinikum)

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